Cochlear implantation (CI) has been used as a treatment option for children with auditory neuropathy spectrum disorder (ANSD) who do not benefit from conventional hearing aids. Up to date, there is no robust indicator for predicting CI outcomes in these patients. In addition, programming settings selected for individual ANSD patients might not be optimal since many ANSD children are not able to provide reliable behavioral responses due to their young ages and/or comorbid conditions. These conditions make the audiologic management of implanted ANSD children extremely challenging and at many times uncertain. The long-term goal of this program of research is to develop objective tools that can be used in clinical settings for accurately predicting post-implant speech perception performance and optimizing programming settings for individual ANSD children. As the first step towards fulfilling this long-term goal, this project aims to evaluate how well electrical stimulation is transmitted by the auditory nerve by evaluating temporal response properties of the nerve in implanted ANSD children. In addition, this project also aims to explore the extent to which neural responses recorded at a peripheral and more central level are correlated with each other and whether they are correlated with speech perception performance in ANSD patients. Specific Aim 1 characterizes temporal response properties of the auditory nerve in pediatric CI users by measuring the electrically evoked auditory compound action potential (ECAP) at different stimulation rates. Both children with ANSD and children with sensorineural hearing loss will be tested. Results from these experiments will provide a better understanding of sources of across-patient variations in post-implant speech perception performance among ANSD children. Specific Aim 2 evaluates the association among temporal response properties of the auditory nerve, gap detection threshold and speech perception performance in implanted ANSD children. Results of these studies should expand understandings of how auditory processing in the central auditory cortex is affected by the input from the auditory nerve. Overall, results of this project could potentially lead to the development of an objective tool for identifying a subgroup of ANSD patients who are unlikely to receive substantial benefit from their devices at an early post-implant stage. In addition, these results could also potentially lead to the development of specific signal processing modifications that might result in improved performance for individual implanted ANSD patients. Therefore, this project has tremendous translational significance.